<template>
  <div>
      <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
          <div class="iconfont header-abs-back">&#xe663;</div>
      </router-link>
      <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
        <router-link to="/home">
          <div class="iconfont header-fixed-back">&#xe663;</div>
        </router-link>
          景点详情
      </div>
  </div>
</template>

<script>
export default {
    name: 'DetailHeader',
    data () {
        return {
            showAbs: true,
            opacityStyle: {
              opacity : 0
            }
        }
    },
    methods: {
        handleScroll () {
          const top = document.documentElement.scrollTop
          if( top > 60 ) {
            let opacity = top / 140
            opacity = opacity > 1 ? 1 : opacity
            this.opacityStyle = {
              opacity
            }
            opacity = opacity 
            this.showAbs = false
          }else {
            this.showAbs = true
          }
        }
    },
    created () {
      window.addEventListener('scroll',this.handleScroll)
    },
    distroyed () {
      window.removeEventListener('scroll',this.handleScroll)
    }
    
}
</script>

<style lang="stylus" scoped>
  @import '~@/assets/styles/varibles.styl'
  .header-abs
    position absolute
    left .2rem
    top .2rem
    width .8rem
    height .8rem
    line-height  .8rem
    border-radius .4rem
    text-align center
    background rgba(0,0,0, .8)
    .header-abs-back
      color #fff
      font-size .4rem
  .header-fixed
    z-index 2
    position fixed
    top 0
    left 0
    right 0
    height $headerHeight
    line-height $headerHeight
    text-align center
    color #fff
    background-color $bgColor
    .header-fixed-back
      width .64rem
      text-align center
      font-size .4rem
      position absolute
      top 0
      left 0
      color #fff

</style>